let intervalID;
    function startChange() {
        if (!intervalID) {
        intervalID = setInterval(changeRandomColor, 1000);
        }
    }
/*     function changeColor() {
        if (document.body.style.backgroundColor !== "black") {
        document.body.style.backgroundColor = "black";
        document.body.style.color = "white";
        } else {
        document.body.style.backgroundColor = "white";
        document.body.style.color = "black";
        }
        } */
        function changeRandomColor() {
            const randomColor = Math.floor(Math.random() * 16777215).
            toString(16);
            document.body.style.backgroundColor = `#${randomColor}`;
            }
        function stopChange(){
            clearInterval(intervalID);
        } 
        document.getElementById("start").addEventListener("click", startChange);
        document.getElementById("stop").addEventListener("click", stopChange);
